1. Technical Field
The present invention relates to a suspension apparatus that is arranged between a vehicle body and a wheel in a two-wheeled vehicle or the like.
2. Related Art
In the related art, in a front fork in a two-wheeled vehicle known as an example of a suspension apparatus, bushes are fixed to an upper portion and a lower portion of an inner circumference of an outer tube, an inner tube is slidably fitted into the outer tube via the upper and the lower bushes, an annular oil chamber that is defined by the upper and the lower bushes is formed in a space between the inner circumference of the outer tube and an outer circumference of the inner tube, and thus a volume compensation chamber is formed to compensate for a volume affected by entry and retreat of a piston rod during a stroke of a piston.
In this type of the suspension apparatus, a hydraulic shock absorber according to JP-A-2009-108884 has a partition wall member which is mounted to the inside on an opening end side of the inner tube so that the partition wall chamber guides the piston rod mounted to the outer tube. The partition wall member is configured to have a cylindrical portion that is formed into a cylindrical shape along an inner circumference of the inner tube, and a bottom portion that is provided to block the bottom of the cylindrical portion. In a state where the cylindrical portion is screwed into the inner tube and the bottom portion is positioned inside the inner tube, using the bottom portion as a reference portion, the partition wall member divides into a working oil chamber that is formed below the bottom portion and an oil reservoir chamber which is formed above the bottom portion. A piston mounted to the piston rod that is fixed to the outer tube slides inside the working oil chamber. The oil reservoir chamber supplies working oil to the working oil chamber and vice versa. The working oil chamber communicates with the annular oil chamber via an oil hole provided in the inner tube, and the working oil freely circulates therebetween. When the hydraulic shock absorber is compressed, the working oil flows from the working oil chamber into the annular oil chamber by a volume taken up by the piston rod entering the working oil chamber by a stroke. When the hydraulic shock absorber is extended, the working oil flows from the annular oil chamber into the working oil chamber by a volume freed up by the piston rod retreating from the working oil chamber by a stroke. Accordingly, a volume affected by entry and retreat of the piston rod is compensated for, and a predetermined damping force is obtained.